Spark-plug.



E. L. SUESS.

SPARK PLUG.

APPUCATION FILED SEPT, I4. 1916.

July 10, 191? unrrnn srarns EDIEUND L. SUESS, F PITTSBURGH, PENTISYLVANIA.

SPAFJK-TPLUG.

Application filed September 14, 1916.

- To all whom may concern:

V ,littsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification.

This invention relates to spark plugs hav ing' two spark gaps, one of which is on the outside of the engine cylinder so that the operation of the-plug may be observed and any defects readily detected.

The invention has for its object to provide an efficient plug of the kind stated, having a few relatively simple parts which can be readily assembled, and which may be easily removed and replaced when they become broken or disordered.

The invention also has for its object to provide a double-gap spark plug which is compact and conforms to. the present standard type of spark plugs.

()ther objects and advantages of the invention will be pointed out in the detailed description appearing hereinafter, and in order that the same may be better understood reference is had to the accompanying drawing, in which Figure l is an elevation of the plug, and

Fig. 2 is an enlarged central vertical section thereof.

Referring specifically to the. drawing, 5 denotes the usual porcelain body of the plug, the same being fitted at one end into a metallic base shell 6 of standard, shape. The shell 8 is reduced at one end and screwthreaded as shown at 7 to screw into the en gine cylinder, and the opposite or' outer end of the shell is formed with a stuffing box which receives a gland 8.- The gland is screw-threaded internally, as shown at 9, and the plug 5 has an intermediate sore threaded portion which is screwed into the gland. Between the bottom inner-end of the gland and the corresponding end of the stuffing box is interposed a washer 10. The plug 5 has a shoulder 11 seating against the outer end of the gland 8. The gland 8 se curely holds the plug 5 in the shell 6,.and leakage of gas isetfectually prevented by a the gland and also by the washer 10.

Extending through the upper part of the plug 5 is a terminal rod 12, which is in axial alinement with a second terminal rod 13 mounted in the lower portion of the plug.

en ted iii, TQI'X.

Serial no. 129,116. a

The rod 13 projects from the cylinder end of the plug, its outer end being one of the sparking terminals or electrodes. The other sparking terminal or electrode is indicated at 1%, the same being connected tothe cylinder end of the shell 6 and located alongside the first mentioned terminal. Four of these electrodes 1e. are provided, the electrode formed by the rod 13 being located therebetween. By providing four electrodes 1% wear is distributed between four points. It will be noted that the electrodes 14; extend in :i curve toward the electrode 13 and terminate alongside the same a short distance back of its extremity. The extreme .end of the electrode 14.- elrtends at an oblique angle to the electrode 13 and then -iscurved outward and extended back to the thereof. this construction. of electrodes i, oilwill not collect thereon, but will run down the same to the bend or curved portion and drop off, thus preventing the collection of-oil on the electrodes eliminating fouling and carbonizing thereof.

The outer end of the plug 5 is reduced and screwthreaded to receive a cap nut 15 having on the inside, at the center, a boss 16 which is screw-threaded, and through which the outer end of the rod 12 The boss 16 seats in a recess 17 in the outer end of the plug and by means of a lock nut 18 screwed on the threaded portion of the rod 12, against the outside of the cap nut 15, the

of the nut 18 has a recess containing a lockwasher 19.

in the upper end of the plug 5 is a transverse sight opening 20 closed at its ends by some suitable transparent material 21. This opening is located to render visible the adjacent ends of the rods 12 and 13, in order that the sparking therebetween may be observed, said adjacent ends of the rods extending into the opening and being spaced to produce a spark gap therein.

The plug 5 has a central opening to receive the upper rod 12, said opening having a diameter to also accommodate a transparent sheath 2:2 surrounding said rod and extending through the opening 20 so as to surround the upper end of the lower terminal rod 13 also. The spark gap produced by the two spaced adjacent ends of the rods 12 and 13 is therefore provided with a transparent closure so that the spark may be observed, and at the same time the sparking points are'protected. With this closure it is not necessary to provide the opening 20 with the transparent closure 21.

The lower end of the sheath 22 seats on the fioor of the opening 20, and its upper end extends to and is engaged by the boss 16 of the nut 15, whereby it is securely held down in place.

The lower terminal rod 13 seats and is held within a central longitudinal opening 23 in the plug 5, said opening being so located that the rod is inalinement with the upper rod 12. The upper end of the rod 13 extends into the opening 20 as hereinbefore described to produce one of the auxiliary sparkingvpoints, and just below the opening 20 said rod has a head or enlargement 24: which is conical and which seats in a corresponding recess formed at the upper end of the opening 23. Over the head is placed an asbestos washer 25 to pack the same tightly in the recess. 24 the rod 12 is wrapped with mica or some other insulating material as indicated at. 26, the same fitting tightly in the opening 23, the diameter of said opening being such as to accommodate the rod 13 and the packing 26 surrounding the same. The packing 26 abuts at one end against the shoulder formed by the head 2%, and its other end terminates some distance inward of the cylinder end of the plug 5 leaving a portion of the opening 23 at this end of the plug open and unobstructed, except that part which is occupied by the rod 13. Below the packing 26 the opening 23 contains a small quantity of cement as indicated at 27, and below the cement is placed a small washer 28 which is slightly larger in diameter than the opening so that when the washer is pushed upward in the opening it will become dished and bind tightly in the opening and around the rod 13. This washer is used as an additional safeguard against any possibility of the rod 13 slipping downward in the plug 5, upward movement being prevented by the head 24. The rod 13 is therefore securely held in the plug 5, and adjustment of the auxiliary sparking points may be made by adjusting the upper rod 12 in the manner hereinbefore described.

The diameter of the opening 23 is such that the head 24 may pass through the same,

cylinder end of the the rod 13 being inserted from the inner or I plug 5., L v The several parts constituting the plug Below the head can be easily assembled and readily adjust ed. Animportant advantage gained by the packing 26 is that the plug will fire even though the porcelain body 5 may become cracked.

I claim:

1. A spark lating material provided with a longitudinal opening and a transverse sight opening intersecting the same, axially alined upper and lower terminal rods mounted in the longitudinal opening, the adjacent ends of said rods extending into the sight opening and being spaced to produce a spark gap therein, a transparent sheath housed'in that part of the longitudinal opening in which the upper terminal rod seats", said sheath surrounding said rod and extending into the sight opening and surrounding that portion of the lower terminal rod which extends thereinto, the lower end of the sheath seating on the floor of the sight opening and its upper end extending to the top of the insulating body, and a nut carried by the top of the insulating body and engaging the upper end of the sheath.

2. A spark plug having a-body of insulating material provided with a transverse sight opening, axially alined upper and lower terminal rods mounted in said'body, the adjacent ends of the rods extending into the opening and being spaced to produce a spark gap therein, the body having a longitudinal opening below the sight opening in which the.lower rod seats, the upper end of the longitudinal opening adjacent to the sight opening being reduced to a conical form, an integral abutment of conical shape on the upper end'of the lower rod, said plug having a body of insu abutment seating in the aforesaid reduced conical portion of the longitudinal opening, a packing surrounding the lower rod behind the abutment, retaining means in the longitudinal opening for the packing, and a packing in .the aforesaid reduced conical end of the longitudinal opening and surrounding the abutment seating therein.

3. In a spark plug, a metallic shell having a stufling box at one end, an internally threaded gland seating in the stuffing box, and a body of insulating material carried by the gland, and having an externally threaded portion to screw thereinto, said body also having an external shoulder seating on the outer end of the gland.

In testimony whereof I ailix my signature in the presence of two witnesses.

EDMUNl) L. SUESS. 

